Another possibility is to use an analog to digital HDMI audio extractor. They are more expensive but don't have to use a USB port, even if most are USB powered you can run them off of a phone charger (500ma).
They can be found for as little as $35 depending on output connections, make sure you get the right outputs (analog RCA, analog 3.5mm jack, etc).
Please mark the question as Answered since I think you found the answer yourself. :-)